HTTPfy

Port 4087 (applusservice)

IANA assigns port 4087 to applusservice: APplus Service.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference
applusservice TCP APplus Service Alfred Weindl -

Registry dates for this port: registered 2008-06-05, last modified 2021-08-09.

Check what is listening on port 4087

Linux: is anything listening on TCP 4087?
sudo ss -tlnp 'sport = :4087'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4087
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4087 '
Windows (Command Prompt)
netstat -ano | findstr :4087
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4087 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4087
From Windows
Test-NetConnection HOST -Port 4087

Block port 4087 in the firewall

ufw
sudo ufw deny 4087/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4087 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4087 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4087' -Direction Inbound -Protocol TCP -LocalPort 4087 -Action Block

Related ports

4085ezmessagesrv4086ftsync4088npsp4089opencore

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.